R1:6449a0ecb2da

Rename some internal "Autoclose" mentions to "Permanent Refs"

Summary: Depends on D20428. Ref T13277.

Test Plan: Grep / reading.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13277

Differential Revision: https://secure.phabricator.com/D20432